Causes and solutions of thermal runaway of lithium battery. Lithium battery thermal runaway is a very dangerous thing, so understand the cause of thermal runaway
The reason and the solution is also a more important thing. It's best to get a warning from the cause of the occurrence
Attention should be paid to prevent the occurrence of heat out of control.
There are several reasons for thermal runaway of lithium battery:
1. External force influence
Under the influence of external force, the lithium battery is affected and deformed, and its different parts are relatively displaced, and the lithium battery cell is affected by external force
Internal collision, extrusion, puncture, etc. The most dangerous is puncture. The conductor is inserted into the battery body, resulting in a direct short circuit between the positive and negative electrodes,
Compared with collision and extrusion, which are only probabilistic internal short circuits, the heat generation in the puncture process is more intense, and the probability of heat out of control is higherHigh.
2. Nonstandard use
The non-standard use of lithium battery generally includes external short circuit, overcharge, over discharge and other forms, of which the most easy to develop into thermal runaway is overcharge.
External short circuit: when two conductors with voltage difference are connected outside the cell, the external short circuit occurs. From external short circuit to thermal runaway, medium
The important link between is that the temperature is too high. When the heat caused by external short circuit cannot be dissipated well, the temperature of lithium battery will rise and the temperature will be high
Touch and heat out of control.
Overcharge: the appearance of high electricity, heat and gas are several common characteristics in the overcharge process. The heating comes from ohmic heat and side reactions.
Over discharge: different from the above situations, the potential danger is much higher than people think. Dissolution and migration of copper ions caused by overdischarge
Copper dendrites with lower potential are formed on the cathode side. With the increasing growth, copper dendrites may penetrate the diaphragm and conduct
Cause serious thermal runaway problem.
3. Use in high temperature environment
It is rare that the ambient temperature is too high, but the high temperature is a link that leads to the final direct contact heating out of control.
The solutions to thermal runaway of lithium battery are as follows:
1. Thermal runaway caused by external force: the best treatment is to replace the faulty lithium battery and remove the problem in the whole
Damaged lithium battery.
2. Thermal runaway due to external short circuit: when the heat cannot be dissipated well, the temperature of lithium battery will rise rapidly, and the high temperature will lead to heating runaway.
Therefore, cutting off the short-circuit current or cooling is the way to suppress the thermal runaway caused by external short-circuit.
Causes and solutions of thermal runaway of lithium battery. When thermal runaway of lithium battery occurs due to some factors, the circuit shall be cut off immediately and the measures shall be taken
Corresponding protective measures. When a large lithium battery pack is used, the charging and discharging shall be standardized to avoid the problem of thermal runaway.